1. Field of the Invention
The present invention relates to a compact disc drive for motor vehicles and more particularly to a loading assistant system for precisely and stably guiding an 80 mm disc onto a turntable when the disc is loaded in a compact disc drive which is designed to be commonly used for both an 80 mm disc and a 120 mm disc.
2. Description of the Prior Art
Generally, there are two types of compact discs, i.e. compact discs having a size of 80 mm and 120 mm in diameter, each of which is played in an 80 mm compact disc drive and a 120 mm compact disc drive for motor vehicles, respectively. As the case may be, the compact disc drive is designed to use both the 80 mm disc and the 120 mm disc in common.
In a general construction of the conventional compact disc drive deck as shown in FIGS. 1-3, the deck includes a body case 1 which is defined by a rectangular frame 11, an upper plate member and a lower plate member, and the case is provided with a turntable 2 in its central portion and an insertion slot 12 at its front end as shown in FIG. 1. A transverse axle 4 is disposed within the body case 1, that is, inside of the insertion slot 12 which acts to draw the inserted disc in the body case 1. The transverse axle 4 is surrounded by rubber material and is axially tapered from opposing ends toward the middle portion so as to progressively move the inserted disc in the central portion of the body case 1.
Further, stopper means 3 is provided in the innermost portion of the body case 1 for supporting the fully-inserted disc.
The stopper means 3 consists of a pair of stoppers 3A, 3B pivotally mounted on the inner portion of the body case 1 by pivot pins 31A, 31B, respectively. The left-sided and right-sided stoppers 3A, 3B include toothed portions 32A, 32B at their respective inner ends which engage with each other to permit simultaneous pivotal movement of the stoppers 3A, 3B, and also include downwardly-angled projections 33A, 33B at their respective leading ends. Particularly, a protrusion 34A projects upwardly from a central portion of the left-sided stopper 3A and a hook 35B is formed in the middle of the right-sided stopper 3B.
In detail, the stopper means 3 supports the inserted disc so that a center of the disc is guided onto the turntable 2 on condition that the stoppers 3A, 3B are not spread out in the case of the smaller 80 mm disc and that the stoppers 3A, 3B are spread out in case of the larger 120 mm disc.
For this purpose, on one side within the body case 1, a locking member 5 for the 80 mm disc is provided to prevent the stopper means 3 from being spread out whereas a pivot lever 8 for the 120 mm disc is provided to release the locking member 5 and so operate the stopper means 3.
The locking member 5 is mounted on the body case 1 by a pivot pin 51 and comprises a left-sided outer end portion 52 extending in a longitudinal direction, a left-sided inner end portion 54 having a latching jaw 53, and a right-sided hook 55 for a spring. The latching jaw 53 of the left-sided inner end portion 54 can releasably lock the protrusion 34A of the left-sided stopper 3A and the right-sided hook 55 is connected with the hook 35B of the right-sided stopper 3B by a spring 71 loaded therebetween as return means 7.
Also, the pivot lever 8 is pivotally mounted on the body case 1 by a central hinge pin 8' and a contact pin 82 at a leading end of the pivot lever 8 is pushed off by the inserted 120 mm disc. Consequently, a follower pin 83 at a rear end of the pivot lever 8 presses and actuates the left-sided outer end portion 52 of the locking member 5.
If the disc to be inserted is the 120 mm disc, for example, an outer peripheral surface of the disc pushes the contact pin 82 of the pivot lever 8 outwardly to actuate the stopper means 3 and then the follower pin 83 at the opposite end presses the outer end portion 52 of the locking member 5 inwardly as seen from FIG. 1.
Pivotal movement of the outer end portion 52 due to such inward pressing causes the inner end portion 54 to pivot outwardly and thus causes the latching jaw 53 of the inner end portion 54 to be released from the protrusion 34A of the left-sided stopper 3A.
As a result, both the stoppers 3A, 3B of the stopper means 3 can be swiveled backwardly at the same time by the interlocking toothed portions 32A, 32B so as to guide the 120 mm disc in an innermost position and chuck the center of the disc onto turntable 2 without preventing the inward movement of the disc. On the other hand, if the disc is drawn out, the stoppers 3A, 3B are restored by force of the return means, i.e. the spring 71 connected between the locking member 5 and the right-sided stopper 3B.
On the contrary, the 80 mm disc enters the body case 1 without being contacted by the contact pin 82 because of its small diameter. Entrance movement of the disc is stopped by contact with the downward projections 33A, 33B of the two stoppers 3A, 3B whose pivotal movement is prevented by locking action of the locking member 5, and the center of the disc is finally chucked onto the turntable 2 in such a position as shown by a chain line with two dots in FIG. 2.
With the above-mentioned loading system, there is no particular problem in inserting and loading the 120 mm disc D1 because the disc simultaneously comes into contact with both the downward projections 33A, 33B of the stoppers 3A, 3B from the moment of insertion owing to its large diameter and the stoppers 3A, 3B are also spread out simultaneously, whereby the center of the disc D1 is easily and precisely seated on the turntable 2.
However, when the 80 mm disc D2 is inserted, it primarily comes into contact with any one of the stoppers due to its small diameter. Particularly when the disc D2 comes into contact with the downward projection 33B of the right-sided stopper 3B, it is loaded on the turntable 2 not in a position that the stoppers 3A, 3B are spread out simultaneously but in a position that the right-sided stopper 3B is more spread out than the left-sided stopper 3A due to backlash of the toothed portions 32A, 32B. As a result, the smaller 80 mm disc D2 is not centered on the turntable 2, which causes poor chucking of the 80 mm disc.